GB1578294A - Rotary drive apparatus and tape recording and/or playback machines incorporating the same - Google Patents

Description

PATENT SPECIFICATION ( 21) Application No 16505/77 ( 22) Filed 20 A

Convention Application No 678704 ( 32) Filed 20 ited States of America (US)

te Specification Published 5 Nov 1980

Gl IB 19126 G 5 R B 164 B:

B 474 BN B 488 B F 2 L IU SC 3 37 Y B 38 Y 475 B 476 E 682 B 781 E OTT ti I ' ( 11) Apr 1977 ( 19) F i N O Apr 1976 in 4 'J B 421 B 443 \ B 48 l B 483 B 93 B \ 6154 ( 54) ROTARY DRIVE APPARATUS, AND TAPE RECORDING AND/OR PLAYBACK MACHINES INCORPORATING THE SAME ( 71) We, DICTAPHIONE CORPORATION a corporation organised and existing under the laws of the State of New York, United States of America, of 120, Old Post Road, Rye, New York, 10580, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: -

This invention relates to drive apparatus for imparting rotary motion to a selected one of two spaced apart rotary members, for example, to bidirectional web driving apparatus which may be used as a tape transport.

In bidirectional driving apparatus, such as in web drive mechanisms, tape transport systems, and the like, it is desirable to provide bi-directional drive capability to the web or tape drive members In some applications, it is often de- sirable to switch rapidly and efficiently from one driving direction to the opposite driving direction For example, in a tape transport system which can be used in a tape recording/ playback apparatus, it often is necessary for an operator to move tape in either fast forward or fast reverse direction Such tape movement may be initiated immediately following a record or playback operation Hence, this movement of tape is the well-known fast-forward or rewind modes wherein tape is selectively moved at a much faster rate than during the record or playback modes.

In some tape transport systems, a relatively low speed motor is utilized for the normal for- ward movement of tape, as during a record or playback mode A fast-forward motor having a relatively higher speed is provided for the fast forward movement of tape and a rewind motor, also having a relatively higher speed, is provided for the rewind movement of tape The selective movement of tape thus requires the selective energization of each of these motors Conse- quently, it has been found that the inherent electrical and mechanical time delays results in 45 a noticeable delay from the time that a motor initially is energized to the time that the corres- ponding tape movement is brought up to proper speed.

This is particularly objectionable during a 50 recording or playback operation Also, the requirement of three motors adds to the bulk and cost of the tape transport system.

In a partial solution to this problem of time delays, some tape transport systems are pro 55 vided with the low speed motor in constant operation A selective transmission coupling is used to selectively transfer the rotary motion developed by this motor to various components of the system, such as the capstan/pressure-roll 60 combination, the take-up reel, and the like.

While this has minimized the delay attending a record or playback operation, the problem of separate high speed motors remains.

In many tape transport systems now in 65 commercial use, the separate high speed motors have been replaced by a single bidirectional high speed motor having a selective trans- mission so as to couple the motor either to the supply or take-up reel Heretofore, two sole 70 noids have been used to control this selective transmission When this type of tape transport system is provided, in, for example, a dictation machine, an additional solenoid must be pro- vided to selectively position the record/play 75 back head in contact with the tape, and some- times still further solenoids are used for braking functions Unfortunately, the use of many sole- noids adds to the power requirements of the machine, increases the bulk and cost of the 80 overall system, requires more complex control and support mechanisms, and, more significant- ly, is a source of distracting noise caused by the energization and de-energization of the various solenoids 85 In an effort to reduce the number of sole- 1 578 294 at Acceptance e- A' 1 D) 9 'J 94 noids in such machines, it has been proposed to control a solenoid so as to exhibit three con- ditions, or states, with the concurrent control of the tape transport system for each condition.

D Tliis requires that the solenoid armature has a fully extended displacement, a fully retracted displacement and an intermediate displacement.

Since, in general, a low-cost solenoid inherently is provided with two conditions wherein its armature either is fully extended or fully retracted, the requirement of an additional con- dition in such a solenoid is attended by relative- ly complex and costly control electronics.

Furthermore, there is the additional problem 1 5 that the intermediate position of the solenoid armature may, over a period of time, vary Consequently, the mechanical function which is to be controlled by this intermediate armature position may be erroneously performed.

In addition to the aforedescribed undesirable aspects of prior tape transport devices such prior tape transport devices also have the disadvantage that the rapid actuation of mechan- ical transmissions invariably creates transient noise which is undesirable in a recording machine Additionally, substantial power is consumed by these solenoid actuating means.

It is an object of the present invention to provide improved apparatus for imparting rotary motion to a selected one of two rotary members.

From one aspect, the present invention con- sists in apparatus for imparting rotary motion to a selected one of two members rotatable about mutually spaced axes, comprising:

drive roll means having a rotatable drive shaft and including contacting means for drivingly contacting a mating portion of a selected one of said rotatable members; bidirectional drive means coupled to said drive roll means; and a tensioned string member having an intermediate portion thereof deployed about said drive roll means, said string member cooperating with said drive roll means such that said drive roll means is displaceable between a first position in driving contact with one of said rotatable mem- bers when said drive means rotates said drive shaft in one direction and a second position in driving contact with the other of said rotatable members when said drive means rotates said drive shaft in the opposite direction.

This invention Finds particular application in a web or tape transport mechanism and particu- larly in a tape transport system for a recording and/or playback device provided with a single two-condition multi-purpose solenoid More specifically, the range of displacement of the drive shaft is constrained when the solenoid is in a first condition, whereby the drive roll means is prevented from contacting either of the rotary members; and this constraint is re- moved when the solenoid is in its second con- dition.

Thus, from another aspect, the invention provides a tape recording andlor playback machine of the type wherein tape is driven in a fast-forward mode from a supply reel to a take- up reel and in a rewind mode from said take-up reel to said supply reel, and wherein said machine includes a two condition, single multi 70 purpose tape-controlling solenoid, the machine further including apparatus for selectively con- trolling the movement of said tape, comprising a rotatable supply reel disc member, and a rotatable take-up reel disc member; drive roll 75 means having a drive shaft, and being operable to selectively contact a peripheral surface on said supply reel and take-up reel disc members; means for bi-directionally driving said drive shaft; a tensioned string member having an 80 intermediate portion deployed about and co- operating with said drive shaft; and control means coupled to said solenoid and operative when said solenoid is in a first condition to maintain said drive roll means out of driving 85 contact with said supply reel and take-up reel disc members, and operative when said solenoid is in a second condition to displace said control means such that said drive roll means is free to selectively drivingly contact one of said supply 90 reel and take-up reel disc members, whereby, by reason of the cooperation of the string mem- ber about the drive shaft, rotation of said drive shaft in one direction displaces said drive shaft along said string member to move said drive roll 95 means into driving contact with said supply reel disc member and rotation of said drive shaft in the opposite direction displaces said drive shaft along said string member to move said drive roll means into driving contact with said take-up 100 reel disc member.

In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which:- Figure 1 is a perspective view of a dictation 105 machine in which drive apparatus embodying the present invention finds ready application; Figure 2 is a perspective view of components comprising the tape transport system which can be used in the dictation machine of Figure 1 110 and which includes drive apparatus embodying the present invention; Figure 3 is a top plan view of the tape trans- port system shown in Figure 2 and including additional elements which are used in the dic 115 tation machine shown in Figure 1; and Figure 4 is a bottom plan view of the system shown in Figure 3.

Referring now to the drawings, wherein like reference numerals are used throughout, the 120 present invention will be described in the environment of a web transport system, such as a tape transport system, used, for example, in a magnetic tape recording andlor playback apparatus One embodiment of such an appara 125 tus is a dictation machine of a type shown, generally, in Figure 1 This dictation machine includes a housing 12 for a chassis (not shown) upon which the various mechanical elements and electronic circuitry are supported 130 3 1 578 294 3 Figure 1 also shows various operator-actuated elements, or control switching devices, to effect dictation and/or playback operations The record medium for the illustrated dictation apparatus 10 is magentic tape of the type which is self-contained in a cassette housing Such a magnetic tape cassette is conventional and com- prises a supply reel and a take-up reel The cassette housing is provided with various apertures to accommodate reel drive spindles to drivingly engage the supply and take-up reels, and to accommodate a record/playback transducer, or head, which is inserted into contact with the tape As is conventional, additional apertures are provided to receive an erase head and a pressure roller, the latter cooperating with a capstan for moving the tape past the various heads In order to accommodate such a tape cassette, the dictation machine 10 is provided with a cassette holder compartment 14 Al- though not shown herein in detail, the cassette holder compartment is provided with a support platform for the cassette housing, various guide mechanisms for the cassette housing and, pre- ferably, a door which is closed to shield the cassette and the machine elements during operation.

Typical of the operator-controlled elements is an eject control 16 which, when actuated, serves to lift the door to the cassette holder compartment and, if a cassette is on its support platform, to eject the cassette for removal A series of control elements or switches, such as push-buttons or touch-sensitive devices, is pro- vided for an operator to selectively control various machine operations For example, a stop control 18 is provided to terminate the operation of the dictation machine 10 and to place the machine in a quiescent mode For example, when the stop control 18 is actuated, tape movement is arrested and the record/ playback head is withdrawn from tape contact.

When placed in this mode, dictation machine is ready for subsequent placement in another operating mode.

The series of control elements also include a rewind control 20 for rewinding the tape from its take-up reel within the cassette housing to its supply reel as well as a fast-forward control 22 to rapidly move the tape from its supply reel to its take-up reel In addition, a scan control 24 electronically scans the moving tape for the presence of predetermined control signals thereon while the tape moves in its fast forward direction As described in greater detail in copending Application No 16506177 (Serial No: 1 578295), these control signals represent various instructions which are useful in guiding a transcriptionist during a transcribe operation.

Hence, when actuated, the scan control 24 causes appropriate control apparatus to detect and indicate the relative locations of such con- trol signals.

An erase control 26 is provided for erasing information previously recorded on the mag- netic tape In general, this erase function is performed while the tape is transported be- tween its supply and take-up reels.

Another series of operator-actuated controls is provided to enable an operator to selectively 70 control the audio characteristics of reproduced information To this effect, a volume control 28, a tone control 30 and a tape-speed control 32 are provided to perform the respective in- dicated functions 75 Yet another series of operator-actuated con- trols is provided, including an on/off switch 34, a speaker control switch 36 and a conference/ dictate switch 38 The illustrated dictation machine 10 is provided with a loudspeaker and, 80 additionally, a microphone assembly 50, to be described, which is used with this dictation machine also is provided with a loudspeaker.

Accordingly, the speaker control switch 36 per- mits an operator to selectively actuate the loud 85 speaker of the dictation machine or the loud- speaker of the microphone assembly for the reproduction of sound, as desired The con- ference/dictate control switch 38 is provided to selectively enable an operator of dictation 90 machine 10 to use this machine for normal dic- tation or, alternatively, to record a conference.

In the latter mode, the amplification gain of the recording circuits is increased.

An optional telephone control switch 40 is 95 provided to selectively enable an operator to use dictation machine 10 to record information directly from a telephone line.

Indicator lights 42, 42 A are provided at the rear of dictation machine 10 for apprising an 100 operator of the condition of the machine.

Positioned adjacent the indicator lights 42, 42 A is a slide index 44 including a scale and movable slide levers 46 and 48 attached to the scale.

Slide lever 46 moves in synchronism with the 105 movement of the cassette tape so as to indicate to the operator his present position in respect to the full length of the tape and moves relative to the slide index 44 to indicate tape position.

The microphone assembly 50 is electrically 110 connected to the control electronics included in dictation machine 10 For convenience, micro- phone assembly 50 is supported on a micro- phone support bracket 52 which may be coup- led to the machine housing 12 Microphone 115 assembly 50 includes a sound transducer 56 for converting audio information into correspond- ing electrical signals, and a loudspeaker 54, described above In addition, various operator- controlled actuating elements 62, 64, 66 and 120 68 are provided to enable an operator to con- trol a dictation operation merely by the selec- tive operation of the indicated elements.

These elements include a multi-function control slide switch 64 which controls various 125 machine functions In one position switch 64 places the machine in a record mode; in another position switch 64 places the machine in a re- wind mode; in still another position switch 64 places the machine in a playback mode; and in 130 1 578 294 1 578 294 yet another position switch 64 places the machine in a neutral or stop mode Switch 68 places the machine in a fast forward tape mode and switch 66, when actuated, places predeter- mined control signals on the tape indicating that succeeding information is intended to be an instruction, or that the end of a selected piece of dictation has been reached It is these control signals which are detected in response to the actuation of the scan control 24 Ele- ment 62 is a light which indicates the operating mode in which dictation machine 10 is con- ditioned.

As shown in Figure l, dictation machine 10 is provided with a tape footage counter 70, which may be a conventional digital counter representing the amount of tape which has been transported, and a reset control 72 adapted to reset the count displayed by the counter 70 to a reference, or zero, indication.

The functions of the aforementioned operator-control elements are self-evident.

Accordingly, in the interest of brevity, further description thereof is not provided.

Referring now to Figures 2,3 and 4, there is illustrated the drive apparatus which can be used in the tape transport system included in the dictation machine shown in Figure 1 In order to facilitate a ready understanding of this drive apparatus, it will be described in a preferred application as a tape transport assembly.

However, the present invention is not limited solely to such an application The tape trans- port assembly 100, best shown in perspective in Figure 2, includes a rotatable member in- cluding a supply reel spindle 102, a rotatable member including a take-up reel spindle 112 and a capstan 1 8 As is conventional, the supply reel spindle 102 and the take-up reel spindle 112 are adapted to be received in the supply and take-up reel hubs, respectively, in- cluded in the cassette housing A supply reel pulley 104 is part of the supply reel spindle, as is a supply reel disc 106 Thus, the supply reel spindle, pulley and disc are adapted for integral rotation As will soon be described, the peri- pheral surface, or rim, of the supply reel disc 106 is adapted to be frictionally driven and, for this purpose, may be provided with suitable material, such as rubber, or the like As shown in the bottom view of Figure 4, the supply reel disc 106 is free to rotate about a fixed shaft 106 a which is secured to the chassis, generally designated by, the reference numeral 80 (Figure 4) In similar fashion, the take-up reel spindle 112 is coupled to a take-up reel pulley 114 and to a reel disc 116, the latter being supported by, and free to rotate about, a suitable shaft 1 16 a (Figure 4) The peripheral surface, or rim, of the reel disc 116 is provided with suitable material to permit the disc to be frictionally driven, as will soon be described.

In the illustrated embodiment, two separate motors 120 and 160 are provided Preferably, the motor 120 is a relatively low speed unidirectional motor and is adapted for constant operation when power is supplied to the dicta- tion machine A pulley 122, coupled to motor receives a drive belt 12 4 entrained there- about to drive a flywheel 126 associated with 70 capstan 128 Thus, capstan 1 28 is continually driven by the motor 120 Drive belt 124 is played about capstan flywheel 1 26 and, addi- tionally, is in driving contact with a slip-clutch pulley 130 Pulley 130 is secured to a drive 75 shaft 132 which, in turn, is journalled for rotation in a support sleeve 134 As shown in Figures 2 and 4, support sleeve 134 is at one end of a pivoting crank arm 136 Pivoting crank arm 136 has legs 136 c and 136 b (Figure 4) dis 80 posed at an angle to each other At the juncture of legs 136 a and 136 b an access bore 136 c is provided to accommodate a pivot shaft 137 A pivoting crank arm actuator 138 is provided at the end of leg 136 b 85 Pivot shaft 137, which may be formed on the chassis, is positioned such that, as the pivot- ing crank arm 136 pivots thereabout, drive shaft 132 is urged into or out of contact with the rim of the take-up reel disc 116 More par 90 ticularly, and as viewed in Figure 2, when a force is applied to the pivoting crank arm actuator 138 so as to pivot crank arm 136 coun- terclockwise about pivot shaft 137 (Figure 4), drive shaft 132 is urged away from the rim of 95 the take-up reel disc 116 Conversely, when a force is applied to the pivoting crank arm ac- tuator 138 to pivot crank arm 136 in the clock- wise direction (Figure 2), drive shaft 132 is urged into contact with the rim of the reel disc 100 116 Since pulley 130 and drive shaft 132 are continuously rotated by the motor 120, con- tact between drive shaft 132 and the take-up reel disc 116 applies a driving force to the reel disc As this disc is so driven, tape is moved 105 from the supply reel to the take-up reel As tape is payed out from the supply reel, the dia- meter of the tape spool wound on the take-up reel increases Consequently, the angular velo- city of the take-up reel disc need not be as high 110 to take up the tape which is moved at constant speed by the capstan; and the drive shaft can be driven at a slower speed But since the drive shaft 132 is driven at a relatively constant speed by motor 120, it effectively is over-driven with 115 respect to reel disc 116 Slip-clutch pulley 130 accounts for this over-drive so that there is slippage between pulley 130 and drive shaft 132 This provides proper tension in the tape as it is wound onto the take-up reel 120 The motion imparted to the take-up spindle is utilized to drive the tape indicator system To this end take-up reel pulley 114 is coupled to another pulley 142 by a drive belt 140 A worm gear 144 is integrally formed on, or may be 125 secured to, the shaft of pulley 142 and is in meshing engagement with a gear 146 Gear 146 is coupled to a slide indicator drive pulley 148 which, in turn, is coupled to the slide indicating mechanism (not shown) by a drive belt 150 130 I i I 1 t n I J./ 1 578 294 Thus, as the take-up reel rotates, the slide indicator drive pulley 148 is also rotated pro- portionately, thereby resulting in a corres- ponding movement of the slide indicator mech- anism This movement can be observed by the operator as the movable slide lever 46 (Figure I) is displaced along the slide index 44.

The motion imparted to the supply reel pulley 104 is utilized to actuate the tape foot- age counter mechanism To this end supply reel pulley 104 is coupled by a drive belt 152 to a pulley 154 A drive shaft 156 coupled to pulley 154 drives a digital counter 158 mounted on a suitable frame member 82 of the chassis 80 (Figure 3) Thus, when the supply reel rotates, a corresponding rotation is effected in the counter pulley 154, resulting in a concomitant change in the count indicated by the counter 158 Thus, counter 158 can be used as the tape footage counter 70 (Figure 1).

Drive shaft 156 is also is secured to a chop- per wheel 155 as shown in Figure 3 Chopper wheel 155 rotates with pulley 154 to periodic- ally interrupt a light beam (not shown) so that, if there is a break in the tape, the supply reel and chopper wheel 155 will not rotate Thus the light beam will not be interrupted This condition is sensed by suitable control cir- cuitry (not shown) and such condition is indi- cated by the control indicator lights 42 and 42 A (Figure 1).

In reversing the direction of tape travel for rewind, and in certain instances for forward tape travel, it is desirable to advance the tape at high speed Preferably, the source of this high speed motive power is a single bidirectional motor 160 Alternatively, separate high speed, unidirectional motors can be provided The drive shaft of motor 160 is coupled by a pulley 162 and drive belt 164 to an idler pulley 166, which, in turn, is coupled by a drive belt 168 to a drive roll pulley 170 Drive roll pulley 170 is rotated at a relatively high speed in the clock- wise or counterclockwise direction, depending upon the rotational direction of motor 160.

Drive roll pulley 170 is secured to drive roll means including a drive shaft 172 whose upper portion terminates in a free end 172 a Secured near the upper portion of drive shaft 172 is contacting means comprising a drive roll 174.

As will soon be described, the assembly com- prised of the drive roll pulley 170, drive shaft 172 and drive roll 174 is adapted to be displaced in a generally lateral direction Accord.

ingly, to support this assembly in the upright position indicated in Figure 2, a support arm or link 173, best seen in Figure 4, is provided, and link 173 is pivoted at 175 about an axis coincident with a line which is also coincedent with the axis of rotation of the pulley 166, said line being perpendicular to a line joining the axes of rotation of the supply and take-up seel spindles 102 and 112 respectively How- ever, it should be pointed out that this support link merely ensures the proper upright position- ing of drive shaft 172 and does not cause or contribute to the generally lateral displacement of the drive shaft.

A single flexible but substantially inexten- sible string member 176, which may be formed 70 of any suitable material, such as a polyester cord, a wire, nylon strands, or the like, has its opposite ends secured by spring members 178 a and 178 b respectively, to suitable posts 180 a and 180 b, respectively, secured to the chassis 75 The spring members 178 a and 178 b perm- anently resiliently tension the string member 176 An intermediate portion 182 of the string member is deployed by being wrapped about the upper end portion 172 a o the drive shaft 80 172 to thus "capture" the drive shaft.

The frictional forces between the tensioned string member 176 and the captured drive shaft 172 imparts a lateral movement to the drive shaft when rotated, so that the drive shaft 85 effectively "walks" along the string member.

For example, when motor 160 rotates drive shaft 172 in a clockwise direction, as viewed in Figure 2, drive shaft tends to be displaced in the right-hand direction This displacement of 90 drive shaft 172 urges drive roll 174 into contact with take-up reel disc 116 In the preferred embodiment of the illustrated apparatus, drive roll 174 frictionally drives the reel disc 116.

Accordingly, drive roll 174, or at least its peri 95 pheral surface, is formed of suitable material (such as rubber or the like) to exert such a frictional drive As the drive roll rotates in a clockwise direction take-up reel disc 116 is driven in a counterclockwise direction and tape 100 is transported from the supply reel to the take- up reel, as in a fast-forward mode.

Conversely, if motor 160 is reversed to rotate drive shaft 172 in a counterclockwise direction, the frictional forces between drive 105 shaft 172 and the tensioned string member 176 imparts an opposite lateral movement to the drive shaft so that the drive shaft "walks" along the string member in the left-hand direction.

This lateral displacement of the drive shaft 110 urges the drive roll 174 into contact with the supply reel disc 106, thereby driving the supply reel in the clockwise direction at a relatively fast speed, as in the rewind mode.

The selective contact of drive roll 174 with 115 either supply reel disc 106 or take-up reel disc 116 is determined by the direction of rotation of drive shaft 172 Once positioned adjacent supply reel disc 106 or take-up reel disc 116 drive roll 174 will remain in contact even after 120 high speed motor 160 has stopped In order to place the apparatus in condition for normal slow speed operation, drive roll 174 must be moved out of contact with discs 106 or 116.

In either the rewind or fast-forward mode, 125 the driving force of drive roll 174 against reel disc 106 or 116 is substantially assisted by a self-locking effect created by selection of cer- tain geometric parameters including the loca- tions of pivot point 175 and spindles or shafts 130 106 a and l 16 a the diameters of discs 106 and 116 and the diameter of drive roll 174 These parameters also include the location of the drive shaft 172 and drive roll 174, throughout the extent of their path ofmovement, bodily above a line joining the axes of the supply and take-up reel spindles 102 and 112 as viewed in Figure 4, i e bodily to that side of the said line on which the pivot point 1 75 of the link 173 is disposed.

As best seen in Figure 4, where reel discs 106,116 and drive roll 174 are shown in dotted line, when drive roll 174 is in driving contact with either reel disc 106 or 116 mechanical re- sistance to the rotation of either reel disc 106 or 116, for example when tape is rewound or moved in a fast-forward mode, creates frictional forces at the rim of drive roll 174 These forces urge drive roll 174 into tighter contact with reel discs 106 or 116 In essence, the drive mechan- ism becomes self-adjusting providing increased drive capability in response to increased load.

This feature eliminates the necessity to create a high string tension in string member 176 which minimizes the power required to rotate drive shaft 1 72 and drive roll 174 and also minimizes excessive wear due to the frictional rubbing of drive shaft 172 and string member 176 The tension in the string member 176 may, however, assist in urging the drive roll into contact with the reel discs 106, 116 by vir- tue of the "V" disposition of the string member, produced by locating the axis of the pivotal mounting 175 of the link 173, and the drive shaft 172 and drive roll 1 74 throughout the extent of their path of movement, on opposite sides of a line joining the posts 180 a and 180 b to which the spring members 178 a and 178 b are anchored.

Normal forward speed operation dictates that the transducer head be moved inwardly to contact the tape in the cassette Such move- ment is determined by a solenoid and mechani- cal linkage The mechanical linkage includes a yoke member 184 which is secured to a link member 190 The yoke member 184 includes a cut-out 186 and a bifurcated end portion 188.

As shown, bifurcated end portion 188 extends outwardly from cut-out 186, and its legs taper outwardly to form cammed surfaces As will be described, yoke member 184 moves longitudin- ally between first and second extreme positions In one of these positions, drive shaft 172 is disposed within cut-out 186 In the other extreme position, the yoke member is effectively cleared of drive shaft 172 Alternatively, the drive shaft can be disposed between the remote ends of the legs of the bifurcated por- tion 188 when the yoke member is in its other extreme position The lateral displacement of the drive shaft 1 72 is constrained when the drive shaft is disposed in cut-out 186, which functions as a detent, but this constraint is re- moved when the yoke member is moved to its other extreme position.

The longitudinal movement of yoke member 184 is determined by the link member 190 which is mechanically coupled to the armature 202 of a solenoid 204 Thus, when solenoid 204 is selectively energized, its armature 202 70 moves between a fully extended position (shown in Figure 2) and a fully retracted posi- tion (shown in Figure 3) relative to the solenoid housing This movement of solenoid armature 202 results in a corresponding longitudinal 75 movement of link member 190 and yoke mem- ber 184 In addition to moving yoke member 184, link member 190 pivots the aforedescribed pivoting crank arm 136 For this purpose, the link member 190 is provided with an abutment 80 192 fixed so as to contact pivoting crank arm actuator 138 and an actuator coupling spring 194 which resiliently couples actuator 138 to link member 190.

With this arrangement, when solenoid arma 85 ture 202 is in its fully extended position, abut- ment 192 contacts pivoting crank arm actuator 138 to pivot crank arm 1 36 in a counterclock- wise direction, as viewed in Figures 2 and 3 (clockwise in Figure 4) Conversely, when sole 90 noid armature 202 is in its fully retracted posi- tion, the movement of link member 190 exerts a corresponding resilient force on pivoting crank arm actuator 138 through the coupling spring 194 to pivot crank arm 136 in a clock 95 wise direction as seen in Figures 2 and 3 (coun- terclockwise in Figure 4).

In addition to selectively limiting the lateral displacement of drive shaft 1 72 and controlling the pivoting motion of arm 136, solenoid 204 100 also controls a record or playback operation.

That is, when a record or playback operation is to be performed, a record/playback head must be brought into contact with the magnetic tape and a pressure roller must be urged against the 105 capstan so as to move the tape past the head.

Conversely, when a record of playback opera- tion is terminated, the record playback head is withdrawn from the tape and the pressure roller is moved away from the capstan This move 110 ment of the head and pressure roller is deter- mined by the movement of link member 190, as best seen in Figure 3.

A bridge support member 210 is provided to support a pressure roller 212 and a record/play 115 back head 214 Pressure roller 212 is conven- tional and functions as an idler roller The record/playback head 214 also may be conven- tional and is adapted to record information on or reproduce information from the magnetic 120 tape as determined by the electronic control and processing circuitry (not shown) connected thereto As is also shown in Figure 4, bridge member 210 includes legs, such as legs 211, which are pivotally mounted on a pivot rod 125 230, the latter being secured to the chassis As described in greater detail in copending Application No 16504/77 (Serial No.

1578293), bridge member 210 is positioned to ensure that pressure roller 212 and record/ 130 v lu}- 1 i 1 578 294 28 to 31, wherein said detent means comprises a bifurcated portion of said yoke having respec- tive cammed surfaces for cooperating with said drive shaft to move said drive roll means away from said respective reel disc member when said solenoid is activated from said second condition to said first condition.

Claims (1)

1. 33 Apparatus for imparting rotary motion selectively to one or other of

   two spaced apart rotatable members, substantially as herein- before described with reference to the accom- panying drawings.

   34 A tape recording and/or playback machine incorporating apparatus as claimed in any of claims 1 to 24 or 33.

   A dication machine substantially as hereinbefore described with reference to the accompanying drawings.

   BARON & WARREN, 16, Kensington Square, London W 8 SHL.

   Chartered Patent Agents.

   Printed for Her Majesty's Stationery Office by MUL'i IPLEX medway ltd, Maidstone, Kent, ME 14 1 JS 1980 Published at the Patent Office, 25 Southampton Buildings, London WC 2 l AY, from which copies may be obtained.

   f-, I,1 1 'I